1. Field of the Invention
The invention relates to a method for detecting a direction of travel or for detecting a change in the direction of travel of a motor vehicle and to a computer program product for carrying out all the steps of the method.
2. Description of the Related Art
Document DE 40 38 284 A1 describes a method for identifying the direction of rotation of an encoder, in which method the encoder is encoded with different scale graduations, specifically both large and small scale graduations. The rotational movements of the encoder are sensed by a sensor. In the course of a rotational movement of the encoder, the direction of rotation of the encoder is identified from the signal pattern of the sensor which correlates with the scale pattern of the encoder or the chronological profile of the sensor signals. Such encoding of the encoder is disadvantageous in that essentially integral multiples of one revolution of the encoder have to be used to calculate the speed of the encoder, as a result of which a speed measurement with such an encoder provides relatively poor resolution.
In document DE 197 21 488 A1, a method for compensating inaccuracies of a wheel speed sensor is proposed in which each scale graduation is assigned a correction factor which is dependent at least on the scale graduation error. This correction factor is taken into account in the speed calculation.
Document DE 41 04 902 A1 describes a method for detecting a direction of rotation in which, on the one hand, a composite signal and, on the other hand, a difference signal are formed from the output signals of two magnetic field sensor elements which are arranged offset with respect to one another in relation to an alternatingly magnetized encoder, and the direction of rotation of the encoder is determined from these signals.